1. Field of the Invention
The invention relates to body building equipment, in general, and, more particularly, to a weight plate having an internal, spring-loaded pin which is externally activated to conveniently, safely and simply ease the selection of weight plates in an exercise apparatus.
2. Prior Art
Bodybuilding equipment (also referred to as physical fitness equipment or exercise apparatus) often takes many forms to provide the resistance necessary to tear down muscle tissue during an exercise regime. Contemporarily, many ingenious resistance developing systems or machines have been developed utilizing, for example, systems which incorporate a selectable weight stack. By design, the known equipment allows a user to, within the module, increase weight as the available resistance is incrementally selectable. These systems often promise faster and better results for exercisers. Although history shows the ingenuity of the advancement of mechanical and/or biomechanics may benefit muscle growth, little or no effort has been made to simplify, make safer and contemporize the selectorized weight stack for over four decades.
Conventional weight stacks are, typically, multiple layers of metal-based plates which collectively amass an aggregate amount of weight. Generally, a weight stack includes a variety of rectangular weight plates, typically one inch thick and about 10 by 4 inches. Each conventional plate known in the art incorporates four boreholes therein. Three throughbores pass vertically through the thickness of the plate from the top surface to the bottom surface. The fourth bore passes horizontally from the front face within the width of the plate (between the top and bottom surfaces) and intersects the middle one of the three bore holes.
Two throughbores engage or receive a pair of spaced-apart guide rods and cause the plate to track vertically thereon. The middle throughbore accommodates a center post. The center post has multiple diametric throughbores therein to act as a recipient for a separate selector pin which passes through the fourth throughbore. Thus, each plate may be independently and selectively engaged as part of the weight stack by manually inserting the selector pin which is, typically, slightly longer than the width of a plate and has a knob of sorts on one end so that a user may better manipulate the selector pin. The pin is inserted through the fourth throughbore in the plate and a throughbore in the center post to lock the weight plate to the center post which is then moved when the apparatus is operated.
Although traditional weight stacks, such as those described above, have succeeded in carrying out the intended purpose, there are many areas for substantial improvement.
One key problem often associated with traditional weight stacks is that the selector pin is removable and is often misplaced, stolen or damaged whereupon it is replaced with a functionally and/or structurally inadequately sized pin. This inappropriate replacement historically has caused bodily injury due to the violation of the inherent design of the apparatus.
The removable pin also permits the user to easily modify the operation of the apparatus outside the manufacturer's design criteria for the plates and/or weight stack.
Additionally, there is a level of dexterity and hand-to-eye coordination required to effect the insertion of the selector pin in the horizontal throughbore of the weight and the center post which further limits the true and effective result.
Therefore, the need exists for a more easily manufactured weight plate having a construction that minimizes confusion on the part of the user, possibility for misuse or failure, and the possibility of injury to the user, yet retains the convenient exchange of weight without danger to the user. The weight plate of the present invention satisfies this need.